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  1.  
  2. // #include <bits/stdc++.h>للاسف مش بينفع هنا
  3. #include <iostream>
  4. #include <vector>
  5. #include <string>
  6. #include <algorithm>
  7. #include <cmath>
  8. #include <map>
  9. #include <set>
  10. #include <unordered_map>
  11. #include <unordered_set>
  12. #include <queue>
  13. #include <stack>
  14. #include <deque>
  15. #include <bitset>
  16. #include <utility>
  17. #include <limits>
  18. #include <iomanip>
  19. #include <sstream>
  20. #include <tuple>
  21. #include <numeric>
  22. #include <functional>
  23. #include <array>
  24. using namespace std;
  25. #define mahmoud                 \
  26.   ios_base::sync_with_stdio(0); \
  27.   cin.tie(NULL);
  28. typedef long long ll;
  29.  
  30.  
  31. int main() {
  32.     mahmoud;
  33.  
  34.     int n, k;
  35.     cin >> n >> k;
  36.     const int ofset = 1000000;
  37.     vector<int>freq(2000001);
  38.     vector<int> v;
  39.     int x;
  40.     while (n--)
  41.     {
  42.         cin >> x;
  43.         v.push_back(x);
  44.         freq[x + ofset]++;
  45.     }int num1,num2;
  46.     int count = 0;
  47.     for (int i = 0;i < freq.size() - 1;i++)
  48.     {
  49.         if (freq[i] > 0) {
  50.             num1 = i - ofset;
  51.             for (int j = i + 1;j < freq.size();j++)
  52.             {
  53.                 if (freq[j] > 0) {
  54.                     num2 = j - ofset;
  55.                     if (num1 + num2 == k)
  56.                     {
  57.                         count += (freq[i] * freq[j]);
  58.                     }
  59.  
  60.  
  61.                 }
  62.             }
  63.         }
  64.     }
  65.     cout << count;
  66.  
  67.     return 0;
  68. }
  69.  
  70.  
Success #stdin #stdout 0.01s 11192KB
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https://ideone.com/IpyNjc
language:
C++ (gcc 8.3)
created:
11 hours ago
visibility:
public

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